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Amended Record of Decision on Winter Use in Yellowstone

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Date: July 21, 2008
Contact: Rick Frost, 970-586-1202
Contact: Al Nash, 307-344-2015

National Park Service
U.S. Department of the Interior

Intermountain Region

Regional Director’s Office
12795 W. Alameda Pkwy.
P.O. Box 25287
Denver, Colorado 80225
July 21, 2008


Rick Frost, National Park Service Intermountain Region (970) 586-1202
Al Nash, Yellowstone National Park (307) 344-2015

Amended decision addresses management of Sylvan Pass

An amended Record of Decision addressing a long-term plan to guide management of winter use over Sylvan Pass in Yellowstone National Park has been signed by Mike Snyder, Director of the Intermountain Region of the National Park Service (NPS).

A November 2007 Record of Decision on winter use in Yellowstone called for the NPS to work with the State of Wyoming, Park County, Wyoming and the City of Cody to explore reasonable avalanche and access mitigation safety measures, which would provide continued snowmobile and snowcoach travel on the park’s East Entrance road over Sylvan Pass.The members of this Sylvan Pass Study Group met several times and discussed safety and access concerns.

In June, the Sylvan Pass Study Group recommended the continued use of a combination of avalanche mitigation techniques to provide for a safe, predictable, limited, core motorized oversnow travel season over Sylvan Pass. The study group agreed the safety of visitors, guides, and NPS employees, was the first priority in avalanche mitigation. They collectively agreed to explore funding of access and safety improvements, and they remain committed to consistent, ongoing communication about these winter operations. The amended record of decision takes into account these recommendations.

Beginning in the 2008-2009 winter season, Yellowstone’s East Entrance and Sylvan Pass will be open for motorized and non-motorized oversnow travel for a limited core season from December 22 through March 1 each winter, subject to weather, safety, equipment, and fiscal constraints.

A combination of avalanche mitigation techniques may be used in Sylvan Pass, including forecasting and helicopter and howitzer dispensed explosives, as well as techniques that may be available in the future. It is the intent of the National Park Service to review and update the previous Occupational Safety and Health Administration and Operational Risk Management Assessment safety evaluations, and to evaluate additional avalanche mitigation techniques in order to further improve safety and visitor access.

Avalanche management at Sylvan Pass may necessitate unscheduled, temporary closures of the road segment through the pass. Management of the avalanche risk cannot guarantee the pass will be open every day of the winter season. 

In addition, beginning this winter, five hundred forty (540) Best Available Technology (BAT) snowmobiles and eighty-three (83) snowcoaches will be allowed per day in Yellowstone, during a winter season which starts on December 15 and ends March 15 each year, weather and snow conditions permitting. Thirty (30) BAT snowmobiles and two (2) snowcoaches will be allowed per day through the park’s East Entrance during the core season of December 22 through March 1. 

All snowmobiles and snowcoaches will continue to be 100% commercially guided, and may travel only on existing park roads groomed for their use. Trail and off-road use of snowmobiles and snowcoaches has always been, and will continue to be, prohibited.

The amended Record of Decision, the original November 2007 Record of Decision, and the Winter Use Plans Final Environmental Impact Statement can be found at the National Park Service’s Planning, Environment and Public Comment (PEPC) website at http://parkplanning.nps.gov/documentsList.cfm?parkId=111&projectId=12047.  These documents are also available in hard copy by writing the Winter Use Planning Team, P.O. Box 168, Yellowstone National Park, Wyoming 82190. Document requests may also be made by sending an e-mail to yell_winter_use@nps.gov; by calling 307-344-2019 during normal business hours; or by sending a request by fax to 307-344-2025.

- www.nps.gov -

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